How to Tell if a Coin is Counterfeit: 7 Easy Tests

As a coin buyer in Chicago with over 45 years of experience, we frequently see collectors and investors bring in coins they believe are rare or highly valuable, only to discover they’ve been scammed by a convincing fake.

If you are evaluating a coin and don’t have a professional numismatist nearby, you need to know what to look for immediately. Here are 7 highly effective ways to test if your coin is a counterfeit.

1. The Magnet Test 

Precious metals like gold and silver are not magnetic. If you are testing a coin that is supposed to be solid silver or gold, place a strong magnet next to it. If the coin sticks or is attracted to the magnet, it is absolutely a counterfeit made of base metals like steel or iron. (Note: This test alone isn’t foolproof, as some fakes use non-magnetic copper or lead, but it is a great first step.)

2. The Weight and Measurement Test 

Government mints operate with strict, exacting standards. Genuine coins have incredibly precise weights, thicknesses, and diameters. Counterfeiters almost always struggle to match both the exact size and the exact weight. Use a digital scale that reads to two decimal places and a set of calipers. Compare your coin’s measurements to the official specifications of that coin. If the density or weight is off by even a few grams, you likely have a fake.

3. The “Ping” Test (For Gold & Silver) 

Base metals sound dull when dropped or tapped. Genuine silver and gold, however, have a distinct, high-pitched, and long-lasting ring. If you balance your coin on one fingertip and gently tap it with another metal object (or drop it flat on a wooden table), a real silver or gold coin will produce a beautiful, lingering “ping.” Fakes will make a short, dull “thud.”

4. The Ice Cube Test 

Silver and gold are incredible conductors of heat. If you place a standard ice cube on top of a genuine silver or gold coin, the ice will begin melting almost instantly (much faster than it would at room temperature).

5. Check for Casting Seams on the Edge 

There are two ways to make a fake coin: striking (like a real mint) or casting (pouring liquid metal into a mold). Cast counterfeits almost always leave a subtle “seam” right down the middle of the coin’s edge. Look closely at the periphery of the coin; if you see a distinct line wrapping around the edge, it is a cast fake.

6. Look for Porosity and Dimples in the Field 

Because counterfeiters don’t have the sophisticated, high-pressure planchets used by real government mints, their fakes often feature poor surface quality. Look closely at the “field” (the flat, blank background areas of the coin). If you see tiny pockmarks, dimples, or a rough, porous texture, it is a clear sign of poor casting.

7. Spot “Added” or “Removed” Mint Marks 

This is a highly deceptive tactic where counterfeiters alter a genuine, common coin to make it look like a rare date. For example:

• Added Marks: 

The 1916-D Mercury Dime is the rarest in the series, so scammers will solder a fake “D” onto a common 1916 dime. The same happens with 1932 Washington Quarters, where a fake “D” or “S” is added to inflate their value.

• Removed Marks: 

A 1922 penny with no mint mark is incredibly rare, but the 1922-D is common. Scammers will physically file off the “D” to fool buyers. Similarly, they will remove the “S” from a 1895-S Morgan Dollar to make it look like the exceedingly rare 1895 plain version.

Spotting these altered mint marks often requires high-power jeweller’s loupes and the trained eye of a professional.

When in Doubt, Consult a Professional 

Counterfeiters are getting more advanced every year, and some fakes are so good that they require third-party authentication.

If you aren’t sure about the authenticity of your collection, don’t guess. Stop by Chicago Gold Gallery today. As Chicago’s premier coin buyer, our trained numismatists will evaluate your coins, determine their true density and authenticity, and can even send them to NGC or PCGS for official grading and encapsulation.

Contact us today to discover the true value of your collection!